During the first year of this Grant the data collection instrument was field-tested and revised. At this time total data abstraction has been completed on 221 patients discharged from two medical wards. 26.7% of these persons had at least one complication and approximately 2-3% had some extended post-hospital disability or permanent disability. Preliminary analyses (we emphasize the preliminary nature of these data) suggest that the degree of severity of illness on admission did not correlate with the likelihood of suffering an iatrogenic illness. On the other hand the age of the patient and the total number of drugs clearly did. During the second year of this Grant, data will be completed on approximately 800 patients, methodologies will be refined to permit more meaningful understanding of the types and numbers of complications observed and what can be done to prevent them.